package com.hmdp.service.impl;

import cn.hutool.core.bean.BeanUtil;
import com.hmdp.dto.Result;
import com.hmdp.entity.VoucherOrder;
import com.hmdp.mapper.VoucherOrderMapper;
import com.hmdp.service.ISeckillVoucherService;
import com.hmdp.service.IVoucherOrderService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.utils.*;
import org.redisson.api.RLock;
import org.redisson.api.RedissonClient;
import org.springframework.aop.framework.AopContext;
import org.springframework.core.io.ClassPathResource;
import org.springframework.data.redis.connection.stream.*;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.script.DefaultRedisScript;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import javax.annotation.PostConstruct;
import javax.annotation.Resource;
import java.time.Duration;
import java.util.Collections;
import java.util.List;
import java.util.Map;
import java.util.concurrent.ArrayBlockingQueue;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

import static com.hmdp.utils.ErrorConstants.USER_HAS_BOUGHT;
import static com.hmdp.utils.ErrorConstants.VOUCHER_NOT_EXIST;

/**
 * <p>
 * 服务实现类
 * </p>
 *
 * @author 没天赋
 * @since 2025-03-09
 */
@Service
@SuppressWarnings(value = "all")
public class VoucherOrderServiceImpl extends ServiceImpl<VoucherOrderMapper, VoucherOrder> implements IVoucherOrderService {

    @Resource
    private ISeckillVoucherService seckillVoucherService;
    @Resource
    private RedisIdWorker redisIdWorker;
    @Resource
    private StringRedisTemplate stringRedisTemplate;
    @Resource
    private RedissonClient redissonClient;

//    //阻塞队列
//    private BlockingQueue<VoucherOrder> orderTasks = new ArrayBlockingQueue<>(1024 * 1024);
    private static final DefaultRedisScript<Long> SECKILL_SCRIPT;

    static {
        SECKILL_SCRIPT = new DefaultRedisScript<>();
        SECKILL_SCRIPT.setLocation(new ClassPathResource("seckill.lua"));
        SECKILL_SCRIPT.setResultType(Long.class);
    }

    //异步处理线程池
    private static final ExecutorService SECKILL_ORDER_EXECUTOR = Executors.newSingleThreadExecutor();

    //代理对象（事务）
    private IVoucherOrderService proxy;

    //在类初始化之后执行，初始化完成后随时可能都有task需要执行
    @PostConstruct
    private void init() {
        SECKILL_ORDER_EXECUTOR.submit(new VoucherOrderHandler());
    }

    //线程池处理任务，类初始化完成后就去stream消息队列拿信息
    private class VoucherOrderHandler implements Runnable {
        @Override
        public void run() {
            while (true) {
                try {
                    //1.获取消息队列中的订单 XREADGROUP GROUP g1 c1 COUNT 1 BLOCK 2000 STREAMS s1 >
                    List<MapRecord<String, Object, Object>> list = stringRedisTemplate.opsForStream().read(
                            Consumer.from("g1", "c1"),
                            StreamReadOptions.empty().count(1).block(Duration.ofSeconds(2)),
                            StreamOffset.create("stream.orders", ReadOffset.lastConsumed())
                    );
                    //2.判断订单是否为空
                    if (list == null || list.isEmpty()) {
                        //如果为空，证明消息队列中没有需要处理的消息，进入下一次循环
                        continue;
                    }
                    //解析数据
                    MapRecord<String, Object, Object> record = list.get(0);
                    Map<Object, Object> values = record.getValue();
                    VoucherOrder voucherOrder = BeanUtil.fillBeanWithMap(values, new VoucherOrder(), true);
                    //3.创建订单
                    createVoucher(voucherOrder);
                    //4.确认消息 XACK
                    stringRedisTemplate.opsForStream().acknowledge("s1", "g1", record.getId());
                } catch (Exception e) {
                    log.error("处理订单异常", e);
                    handlePendingList();
                }
            }
        }
    }

    private void handlePendingList() {
        while (true) {
            try {
                //1.获取pending-list中的订单信息 XREADGROUP GROUP g1 c1 COUNT 1 BLOCK 2000 STREAMS s1 0
                List<MapRecord<String, Object, Object>> list = stringRedisTemplate.opsForStream().read(
                        Consumer.from("g1", "c1"),
                        StreamReadOptions.empty().count(1),
                        StreamOffset.create("stream.orders", ReadOffset.from("0"))
                );
                //2.判断订单是否为空
                if (list == null || list.isEmpty()) {
                    //如果为空，证明PenddingList中没有需要处理的消息，结束循环
                    break;
                }
                //解析数据
                MapRecord<String, Object, Object> record = list.get(0);
                Map<Object, Object> values = record.getValue();
                VoucherOrder voucherOrder = BeanUtil.fillBeanWithMap(values, new VoucherOrder(), true);
                //3.创建订单
                createVoucher(voucherOrder);
                //4.确认消息 XACK
                stringRedisTemplate.opsForStream().acknowledge("s1", "g1", record.getId());
            } catch (Exception e) {
                log.error("处理pending订单异常", e);
                try {
                    Thread.sleep(50);
                } catch (Exception ex) {
                    ex.printStackTrace();
                }
            }
        }
    }

    //在数据库中添加优惠券订单
    private void handleVoucherOrder(VoucherOrder voucherOrder) {
        //1.获取用户
        Long userId = voucherOrder.getUserId();
        //2.创建锁对象
        RLock redisLock = redissonClient.getLock("lock:order:" + userId);
        //3.尝试获取锁
        boolean success = redisLock.tryLock();
        //4.判断获取锁是否成功
        if (!success) {
            //获取锁失败，直接返回失败
            log.error(USER_HAS_BOUGHT);
            return;
        }
        try {
            proxy.createVoucher(voucherOrder);
        } finally {
            //释放锁
            redisLock.unlock();
        }
    }

    @Override
    public Result seckillVoucher(Long voucherId) {
        //获取用户
        Long userId = UserHolder.getUser().getId();
        //获取订单id
        long orderId = redisIdWorker.nextId("order");
        //  1.执行lua脚本
        Long result = null;
        result = stringRedisTemplate.execute(
                SECKILL_SCRIPT,
                Collections.emptyList(),
                voucherId.toString(),
                userId.toString(),
                String.valueOf(orderId)
        );
        int r = result.intValue();
        //2.判断返回状态是否为0
        if (r != 0) {
            // 2.1.不为0，代表没有购买资格
            return Result.fail(result == 1 ? VOUCHER_NOT_EXIST : USER_HAS_BOUGHT);
        }
        //3.获取代理对象
        proxy = (IVoucherOrderService) AopContext.currentProxy();
        //4.返回订单id
        return Result.ok(orderId);
    }

   /* @Override
    public Result seckillVoucher(Long voucherId) {
        //获取用户
        Long userId = UserHolder.getUser().getId();
        //获取订单id
        long orderId = redisIdWorker.nextId("order");
        //  1.执行lua脚本
        Long result = null;
        result = stringRedisTemplate.execute(
                SECKILL_SCRIPT,
                Collections.emptyList(),
                voucherId.toString(),
                userId.toString(),
                String.valueOf(orderId)
        );
        int r = result.intValue();
        //2.判断返回状态是否为0
        if (r != 0) {
            // 2.1.不为0，代表没有购买资格
            return Result.fail(result == 1 ? VOUCHER_NOT_EXIST : USER_HAS_BOUGHT);
        }
        VoucherOrder voucherOrder = new VoucherOrder();
        //2.2.订单id
        voucherOrder.setId(orderId);
        //2.3.用户id
        voucherOrder.setUserId(userId);
        //2.4.代金券id
        voucherOrder.setVoucherId(voucherId);
        //2.5.放入阻塞队列
        orderTasks.add(voucherOrder);
        //3.获取代理对象
        proxy = (IVoucherOrderService) AopContext.currentProxy();
        //4.返回订单id
        return Result.ok(orderId);
    }*/

    /*@Override
    public Result seckillVoucher(Long voucherId) {
        // 1.查询优惠券
        SeckillVoucher voucher = seckillVoucherService.getById(voucherId);
        //2.判断秒杀是否开始
        if (voucher.getBeginTime().isAfter(LocalDateTime.now())) {
            //尚未开始
            return Result.fail(ErrorConstants.VOUCHER_NOT_BEGIN);
        } else if (voucher.getEndTime().isBefore(LocalDateTime.now())) {
            //已经结束
            return Result.fail(ErrorConstants.VOUCHER_IS_END);
        } else if (voucher.getStock() == 0) {
            //库存不足
            return Result.fail(ErrorConstants.VOUCHER_NOT_EXIST);
        }

        //3.一人一单
        //3.1.用户id
        Long userId = UserHolder.getUser().getId();

        //创建锁对象
//        SimpleRedisLock lock = new SimpleRedisLock("order:" + userId, stringRedisTemplate);
        RLock lock = redissonClient.getLock("lock:order:" + userId);
        //获取锁对象
        boolean isLock = lock.tryLock();
        //加锁失败
        if (!isLock) {
            return Result.fail(ErrorConstants.USER_HAS_BOUGHT);
        }
        try {
            // 获得代理对象（事务）
            IVoucherOrderService proxy = (IVoucherOrderService) AopContext.currentProxy();
            return proxy.createVoucher(voucherId);
        } finally {
            //释放锁
            lock.unlock();
        }
    }*/

    /**
     * 一人一单修改数据库
     *
     * @param voucherOrder
     */
    @Transactional
    public void createVoucher(VoucherOrder voucherOrder) {
        Long userId = UserHolder.getUser().getId();
        Integer count = query().eq("user_id", userId).eq("voucher_id", voucherOrder).count();
        //3.2.判断是否存在
        if (count > 0) {
            //购买过返回异常
            log.error(USER_HAS_BOUGHT);
            return;
        }
        //4.扣减库存
        boolean success = seckillVoucherService.update()
                .setSql("stock = stock - 1")
                .eq("voucher_id", voucherOrder) //where voucher_id = #{voucherId} and stack > 0
                .gt("stock", 0)
                .update();
        //5.扣减失败则库存不足
        if (!success) {
            log.error(VOUCHER_NOT_EXIST);
            return;
        }
        save(voucherOrder);
    }
}
